Electronic therapeutic apparatus



e 1963 P. c. CULVER ETAL 3,076,937

ELECTRONIC THERAPEUTIC APPARATUS LiZJ n'nu' no Filed Jan. 4, 1960 afar-200E b I I I DI 0 0a m 5 5 m 0 [N 0 2 ma PERRIN C. CULVER OLIVER P. BLAKE INVENTORS.

Y 64 B ATTORNEYS.

d dlhlhdl Fate-ranted Feb. 5, 1953 free Calif.

Filed Jinn. i, 1960, Ser. No. 94 2 Claims. (Cl. 328-31) The present invention relates to improved means and techniques for developing pulses which are particularly useful for therapeutic purposes.

Pulse generating apparatus for therapeutic purposes has heretofore been proposed in which the pulses applied to the human body through suitable electrodes were in the nature of constant intensity pulses, either of the same polarity or alternately of different polarity. In accordance with an important feature of the present invention, the form of the pulses applied to the human body are not of constant intensity but during each cycle are of changing amplitude, starting from substantially zero amplitude to a maximum amplitude after which the pulse train is interrupted and then started anew beginning again with a pulse of small amplitude. Using such pulse trains of increasing amplitude, increasing generally at a logarithmic rate, the muscles or other parts of the human body are gradually accustomed to the stimulus produced by the pulses in such a manner that the pulses are more effective, and less discomforting.

It is therefore an object of the present invention to provide a different stimulus to the human body for therapeutic purposes.

Another object of the present invention is to provide apparatus for accomplishing these purposes which is relatively simple, inexpensive and easily adjusted for various purposes.

Another object of the present invention is to provide an improved therapeutic method.

Another object of the present invention is to provide improved apparatus for developing a train of pulses having an amplitude which increases with each succeeding ulse.

p The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. This invention itself, both as to its organization and manner of operation, together with further objects and advantages thereof, may be best understood by reference to the following description taken in connection with the accompanying drawings in which:

FEGURE 1 illustrates a system embodying features of the present invention.

FIGURE 2 represents diagrammatically the functioning of the motor driven switching element shown in FIG- URE 1.

FIGURE 3 illustrates the nature of the pulses appearing at the electrode terminals in FIGURE 1.

The apparatus shown in FIGURE 1 functions to develop pulses of the character shown in FIGURE 3 across the electrode terminals 16 and 11 or across the other pair of electrode terminals 12, 13. Thus two different parts of the body may be stimulated simultaneously with the electrical pulses illustrated in FIGURE 3 or the pulses may be applied to two different individuals simultaneously.

These pulses are developed from a source of alternating current represented by the source 14 which has one of its terminals connected through the On-Oif switch 15' to one terminal of the primary winding 16 of transformer 17, the other terminal of the winding 16 being returned to the other terminal of source 14 through either switch 19 or switch 20 depending upon the position of the motor driven cam 22. As shown, the cam 22 is in a position wherein the switch 19 is closed and the switch 29 is opened. Normally in operation of the apparatus the switch 15 remains closed.

The cam 22 may be driven at various adjustable speeds and for the present purposes in described as rotating at a speed of 20 revolutions per minute, i.e. one-third of a revolution per second.

The cam 22 is so shaped as to operate the switches 19 and Eli as indicated in FEGURE 2 wherein one complete revolution of the cam 22 is represented by the angular distance, 360. In one such cycle, i.e. 360, the switch 1% is closed for there being a 30 interval during which neither switch 19 nor switch 2% is closed, followed by a time interval corresponding to 150 during which only switch 219 is closed; and during the remaining 30 neither switch It? nor switch Zil is closed. It is noted that this time interval represented by 369 corresponds also to a time interval of three seconds since that is the time required for the cam 22. to rotate through 360 when the speed of the cam 22 is adjusted to rotate at a speed of 20 revolutions per minute.

it will thus be seen that the primary winding 16 of transformer 17 is periodically energized and de-energized as indicated also in FIGURE 2.. By these means, as explained in detail further, the cathodes 25' and 26 of tubes 27 and 23 respectively are heated and then allowed to cool for the general purpose of obtaining a train of pulses of rising amplitude as indicated in FIGURE 3.

For these purposes the tubes 27 and 28 are of the type in which the heater itself constitutes the cathode of the tube so that there will be inappreciable time lag between application of heating current and heating of the cathode. While the tubes 2'7 and 28 are shown as being of the pentode type, the same may be, for example, of the triode type or screen grid type.

The heaters 25 and 26 each have their terminals connected to corresponding terminals of secondary windings 29 and 30 respectively.

The other secondary winding 32, which is center-tapped, has its outside terminals connected respectively to one terminal of the heaters 25 and 26 with the center tap of winding 32 being connected jointly to the following elements, namely the screen grids 33 and 341 of tubes 27 and 25d and the center tap of transformer winding 36.

Rcsistances 37 and 33 interconnect respectively the control grid 39 of tube 27 to the heater 25 and the control grid 4% of tube 23 to heater 26. The anodes ll and 42 of tubes 27 and respectively are connected to corresponding outside terminals of the transformer winding 36; and there are cross connections between the anode and control grid of different tubes established by condensers and 44' respectively. It is noted that condenser 43 interconnects the anode 42 with the control grid 39; and that the condenser 44 interconnects the anode 41 to the control grid 46.

Two secondary or output transformer windings 47 and 45; are provided. The output voltage across winding 47 is applied to the outside terminals of potentiometertype resistance 59 through switch 51; and likewise, the voltage developed across the output winding it? is applied to the potentiometer resistance through the cam-operated switch 52.

It is noted that the output terminal ii is connected to the adjustable tap on resistance 49; and similarly, the electrode terminal 13 is connected to the adjustable tap on resistance 5% for adjusting the average voltage appearing respectively across the terminals ill, 11 and l2, 13.

For the present purposes the resistances 37 and 38 each have a value of l megohm; and the condensers .3 and 44 each have a vame of 5 microfarads. The tubes 27 and may be of the RCA type 3V4.

it is observed also that when switch 19 is closed, switch 51 is also closed and switches 52 and 2d are open. Likeamass"? wise, when the cam 22 is rotated through 180 from its position shown in FIGURE 1, the switches 52 and 29 are each closed and the switches 19 and 51 are open.

, It is noted also that the three-second time interval shown in FIGURE 2 is considerably longer than the frequency of the AG. supply source 14 which in this case is 60 cycles per second, corresponding to the condition shown in FIGURE 3 wherein the distance between pulses of the same polarity is represented by one-sixtieth of a second.

The operation of the circuit shown in FIGURE 1 may be described generally as follows. Assuming that the voltage across primary winding 16 increases (as it does becauseit is an A.C. voltage) in the direction to make the right-hand terminal increasingly more positive than the left-hand terminal, as indicated by the plus and minus signs adjacent winding 16. This causes a voltage to be induced in the winding halves 32B, 32C of winding 32 of the polarity indicated by the plus and minus signs. Thus, the tap 32A is more positive than the left-hand terminal of winding 32B and more negative than the right-hand terminal of winding 32.

The voltage across winding 32B causes the control grid 39 to become positive with respect to its cathode since a condenser charging current flows through resistance 37 through the following path, namely from tap 32A, through the winding half 36C of winding 36, through condenser 43, resistance 37 and winding half 32B. This current flow through winding half 36C causes a back or counter-electromotive force to be developed in winding halfv 36C of the polarity indicated by the plus and minus signs adjacent winding half 36C. It is noted, of course, that this current through resistance 37 causing the grid 39 to become positive with respect to its cathode 25 changes in accordance with not only the original assumed change of voltage across winding 16 but also, more effectively, by the time constant of the circuit, including condenser 43, in which it is connected.

Thus, initially the tube 27, having a high positive grid voltage, is in an optimum condition, and indeed a space current then flows through tube 27 in a circuit which extends from the tap 32A, through winding half 3613, through tube 27 and winding half 323. This space current produces a back or counter-electromotive force across winding half 363 having the polarity indicated by the plus and minus signs. This voltage across 368 at this time exceeds the voltage across winding half 36C because the space current is greater than the charging current for condenser 43 and, indeed, the space current through wind ing half 3613 causes a voltage to be developed in winding half 36C of polarity opposite to that indicated by the plus and minus signs adjacent winding half 36C to further charge condenser 43 in the same direction to render grid 39 more positive. Hence the space current through tube 27 and winding half 3213 increases rapidly, more rapidly than the originally assumed variation in voltage across primary winding 16. It can also be demonstrated in like manner that when the voltage across winding 16 later starts to vary in the opposite direction, during the sarne half of the" alternating current cycle the space current through tube 27 and winding half 36B decreases substantially just as rapidly as it originally increased with the res'ult that during each alternate half cycle of the AC. supply voltage there is produced a peaked output voltage represented bythe voltage peaks 61 in FIGURE 3.

In like manner it can be demonstrated that the space current flow through similarly connected tube 28 produces peaked output voltages during the other alternate half cycles of the supply voltage as represented at 62 in FIG- URE 3.

In furtherance of this performance it will be seen that when the current flow through one of the tubes 27 or 28 increases, the voltage on the corresponding anode 41 or 42 is depressed and such depressed voltage is transferred to the grid-s of opposite tubes 28 or 2.7 through corresponding cross-connected condensers 44 and 43 to tend to maintain the non-conducting tubes in a non-conducting state.

The above operation has been described in relation to events occurring during a short time interval, i.e. onesixtieth of a second which is very short in comparison to three seconds, i.e. the frequency of operation of cam switch 22. Operation of cam switch 22 super-imposes another variation represented generally by the curved lines 64 in FIGURE 3, which lines represent the maximum values the voltage peaks 61, 62 assume as a result of increased electron emission of cathode-heaters 25, 26 while the tubes 27 and 28 are heating to their maximum temperature. After this maximum temperature is assumed, heating current to the tubes 27, 28 is interrupted (30 regions in FIGURE 2) and the tubes are allowed to cool. Thus alternate heating and cooling of the tubes 27, 28 together with the blocking oscillator type of action discussed above in connection with the electrical operation of tubes 27, 28 results in the production of successive trains of waves wherein each train, represented in FIGURE 3, comprises a series of peaked voltages of alternate polarity with each successive peaked voltage increasing in intensity. The average intensity of such trains may be adjusted by adjustment of the taps on potentiometers 4 9 and 50.

While the particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from this invention in its broader aspects and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

We claim:

1. In an arrangement or" the character described, a source of alternating current, a transformer having a primary winding and a secondary winding, said primary winding being coupled to said source, a pair of tubes each having a heater-cathode, a control grid and an anode, means coupling each one of said heater-cathodes to said source for heating the same, said secondary winding having a center tap, a coil having a center tap, the center tap of said coil and the center tap of said secondary winding being interconnected, opposite ends of said coil being connected to a corresponding anode of said tubes, a first condenser being interconnected between the control grid of one of said tubes and the anode of the other of said tubes, a second condenser being interconnected between the control grid of said other tube and the anode of said one tube, a first resistance connected between the control grid and heater-cathode of said one tube, a second resistance connected between the control grid and heater-cathode of said other tube, opposite ends of said secondary winding being connected to a corresponding cathode of said one and other tubes, and utilization means coupled to said coil.

2. Anarrangement as set forth in the next preceding claim including means for alternately connecting and disconnecting said source from 'said primary winding at a rate substantially greater than the periodicity of said source.

References Cited in the tile of this patent UNITED STATES PATENTS 1,375,739 Scriven Apr. 26, 1921 1,514,746 Wappler Nov. 11, 1924 1,652,148 Olney Dec. 6, 1927 1,671,969 Carpenter June 5, 1928 1,999,729 Kinney Apr. 30, 1935 2,170,884 Winter Aug. 29, 1939 

1. IN AN ARRANGEMENT OF THE CHARACTER DESCRIBED, A SOURCE OF ALTERNATING CURRENT, A TRANSFORMER HAVING A PRIMARY WINDING AND A SECONDARY WINDING, SAID PRIMARY WINDING BEING COUPLED TO SAID SOURCE, A PAIR OF TUBES EACH HAVING A HEATER-CATHODE, A CONTROL GRID AND AN ANODE, MEANS COUPLING EACH ONE OF SAID HEATER-CATHODES TO SAID SOURCE FOR HEATING THE SAME, SAID SECONDARY WINDING HAVING A CENTER TAP, A COIL HAVING A CENTER TAP, THE CENTER TAP OF SAID COIL AND THE CENTER TAP OF SAID SECONDARY WINDING BEING INTERCONNECTED, OPPOSITE ENDS OF SAID COIL BEING CONNECTED TO A CORRESPONDING ANODE OF SAID TUBES A FIRST CONDENSER BEING INTERCONNECTED BETWEEN THE CONTROL GRID OF ONE OF SAID TUBES AND THE ANODE OF THE OTHER OF SAID TUBES, A SECOND CONDENSER BEING INTERCONNECTED BETWEEN THE CONTROL GRID OF SAID OTHER TUBE AND THE ANODE OF SAID ONE TUBE, A FIRST RESISTANCE CONNECTED BETWEEN THE CONTROL GRID AND HEATER-CATHODE OF SAID ONE TUBE, A SECOND RESISTANCE CONNECTED BETWEEN THE CONTROL GRID AND HEATER-CATHODE OF SAID OTHER TUBE, OPPOSITE ENDS OF SAID SECONDARY WINDING BEING CONNECTED TO A CORRESPONDING CATHODE OF SAID ONE AND OTHER TUBES, AND UTILIZATION MEANS COUPLED TO SAID COIL. 